Pearl Jam 20th Anniversary at Alpine

A fan walks on a Pearl Jam designed floor covering while attending the band's 20th anniversary tour at Alpine Valley in East Troy, Wisconsin, on Saturday, September 3, 2011.

A fan walks on a Pearl Jam designed floor covering while attending the band's 20th anniversary tour at Alpine Valley in East Troy, Wisconsin, on Saturday, September 3, 2011. (Chris Sweda/ Chicago Tribune)

A group of Pearl Jam fans mimic the front album of Ten by Pearl Jam while visiting the Pearl Jam museum during the bands 20th anniversary tour at Alpine Valley in East Troy, Wisconsin, on Saturday, September 3, 2011.

A group of Pearl Jam fans mimic the front album of Ten by Pearl Jam while visiting the Pearl Jam museum during the bands 20th anniversary tour at Alpine Valley in East Troy, Wisconsin, on Saturday, September 3, 2011. (Chris Sweda/ Chicago Tribune)